O2 wire help please.
Thread Starter
Instructor
Joined: May 2014
Posts: 106
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From: Miami FL
O2 wire help please.
I installed lg street headers in my c5 z06. The kit came with two o2 wire extensions. I installed the headers and only two o2 sensors instead of all four because the two front ones did not reach the conection. I have the original rear o2 sensors in the front position of the new headers and have the extensions on them. The extensions change the conection from the flat long style connector to the squar style which the front used. When i tuned the car today my tuner told me he could not do a street tune because the ecu is not reading the front o2's. WTF does anyone know what i should do. And i know its kind of complicated but some of you kmight know what im talking about. remember there are four o2 sensors. fronts and rears. the front and rear have different connections. If anyone has installed these headers im sure they can help me. Also the two connectors taht arent being used are fried. any help where i can purchase new ones. This is complicated as hell but i need help. thanks
Pro
Joined: Apr 2010
Posts: 621
Likes: 1
From: westland mi
St. Jude Donor '12
buy the correct front o2 extensions, i have one if your interested, just delete the rear- your tuner can do that, question do you still have cats on the car? also if your in need of a air fuel gauge message me
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Just to make sure, the rear O2's are installed in the front position and there are no O2's in the rear (as I recall the LG's don't have rear bungs installed anyhow). You have the electrical cable adapter to convert the rear O2 plugs so it can be plugged into the front O2 location. Also, from memory, the front O2 connection was a flat plug and the rear was square. The photo below is my installation of LG's although they are no longer on the car. The square plugs is the plug from the rear O2, which runs through an adapter to the flat connection for the front O2 wires to the computer. So, in summary, your rear O2 square connection should be converted to a flat connection and then plugged into the flat connector on the same side of the car (i.e., driver's side O2 to driver's side flat connector on frame, passenger's side O2 to passenger's side flat connector on frame).
Is this how you have it connected?
Is this how you have it connected?
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
..... So, in summary, your rear O2 square connection should be converted to a flat connection and then plugged into the flat connector on the same side of the car (i.e., driver's side O2 to driver's side flat connector on frame, passenger's side O2 to passenger's side flat connector on frame)..........
That is how mine is set up with LG headers also.
I am told the rear O2 sensors have a better heater circuit than the fronts and work better in a header application since the O2 is further down the exhaust than stock (so it doesn't get as much heat and needs the better heater circuit.) Mine has the rear O2 sensors with an adapter to plug them into the front O2 position on the harness.
You need the O2 sensors in the front location, since they are what control the feedback to the computer for tuning rich/lean. The sensors plugged in the rear location check for catalytic converter function, but serve no purpose on keeping the car tuned. The rear position in the harness can be tuned out so that without the O2 sensors you don't get a check engine message and DTC codes.
Good luck.
1st Gear
Joined: Jun 2018
Posts: 1
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Ls1 2004 Corvette o2 sensor
I have tried to do a plug and play with my harness by pulling out extra wires. Working my way down the harness I have got 2 brown wires one to each o2 sensor. Think these are power wires from the block with all the pink wires. Video showed pulling all these wires out but I'm not sure on these two. Do I just cut them or what? Tks
